Subdivide hexagon surface into equilateral triangles
Well after some fumbling around I found a way to do it non-destructively.

You first have to subdivide your hexagon once by hand, you can do subsequent steps procedurally using modifiers


Poke the faces of your NGON hexagon with Alt + P
Eliminate every other radial edge so you end up with three quads
Add a Subdivide modifier set to Simple
Then add a Triangulate modifier
Adjust the subdivision level through the Subdivide modifier